There will be no deal on resurrecting the Northern Ireland power-sharing institutions this week, a senior DUP source has said.

And one of the major stumbling blocks in the ongoing talks is the role, if any, an Irish language commissioner would have.

Hopes of a deal were high in recent days and, with the arrival of Prime Minister Theresa May and Taoiseach Leo Varadkar, it was widely assumed an agreement was just to be signed off and the photocall arranged.

"But the PM was brought over to put pressure on .. and we won't be be bounced into anything.

"It's looking precarious now."

The source said on Monday morning the Assembly group met and party officers had met earlier.

"There was never a deal until everyone signed off on it," said the source.

"We are concerned about how much this will cost. Will the public lose out?"

Speculation over the type of deal the DUP and Sinn Fein have worked out led to DUP leader Arlene Foster coming out saying much of the reporting on what had been agreed was not "grounded in any sort of reality".

She also ruled out any laws that would require bilingual road signs in Northern Ireland and compulsory teaching of Irish in schools.

Northern Ireland has been without devolved government for just over 400 days and an Irish language act has been a key demand of Sinn Fein in the past 13 months.

Sources have suggested three pieces of legislation – an Irish Language Act, an Ulster Scots Act and a broader Culture and Respect Act – could be a means to satisfy both sides.

It's thought the major stumbling block in the talks is the role of an Irish language commissioner and what powers they may hold.

"If that is agreed then there is a fear that whatever does not get agreed then the commissioner will be used to get them through the courts.

"If there is no bilingual road signs, then the commissioner could argue people are being denied their rights and it could end up in court.

"Like the way the human rights commissioners or equality commissioners work. Just look at how the Ashers Bakery decision was made."

Christian-owned bakery Ashers lost a landmark court case after it was found by the Equality Commission to have breached equality laws by refusing to bake a cake with a slogan supporting same-sex marriage.

The Supreme Court is to hear the final appeal in case at the end of April in Belfast.

The DUP has also issued a pro-forma letter to its representatives should they come under pressure from constituents in terms of what is being agreed between it and Sinn Fein.